Stabbing With Syringe in Nigeria Raises Concerns of Ebola as Weapon

A federal air marshal was stabbed with a syringe at the airport in Lagos, Nigeria, on Sunday, an incident that is raising concerns about whether the deadly Ebola virus could be harvested from the widespread outbreak in West Africa and used as a bioweapon.

Initial tests on the substance in the syringe, conducted at a special biodefense forensics laboratory at Fort Detrick, Md., did not detect the virus or any other threatening agent, a spokesman for the Federal Bureau of Investigation, Christos Sinos, said Wednesday. The marshal, who arrived in Houston on Monday, was examined there and has been released from the hospital with no sign of illness, according to a spokesman for the Transportation Security Administration.

Experts say it would be extremely hard for a group to grow large amounts of the virus and turn it into a weapon that could be dispersed over a wide area, infecting and killing many people.

“The bad guys are more likely to kill themselves trying to develop it,” said Dr. Philip K. Russell, a retired major general who was the commander of the Army Medical Research and Development Command.

But it is harder to totally discount the possibility of a smaller attack, perhaps like the one at the airport in Lagos. Another possibility would be suicide infectors, people who deliberately infected themselves and carried the virus out of the epidemic zone to sicken others.

“To truly isolate the virus takes a lot of resources,” said Dr. Ryan C. W. Hall, a Florida psychiatrist who has written about the psychiatric impacts of bioterrorism attacks. “But if you have people who are willing to die and willing to inject themselves with the blood of someone who has been infected, you don’t need a Biosafety Level 4 lab,” he said, referring to the special containment facilities used to work with the most deadly pathogens.

Such an attack would not kill many, or even any, people in an advanced country like the United States. But it could strike terror and cause economic disruption. “Someone gets sick on an airplane, conceivably everyone on that airplane has to be quarantined,” said Dr. Robert Kadlec, who was special assistant on biodefense policy to President George W. Bush.

The United States government considers Ebola and other hemorrhagic fever viruses to be among the most serious potential bioterrorism agents, along with those that cause smallpox, anthrax, botulism, plague and tularemia.

“It’s not very contagious compared to things like plague, but it does have high lethality and could cause fear and terror,” said Dr. Amesh Adalja, a senior associate at the Center for Health Security, which is affiliated with the University of Pittsburgh Medical Center.

Most of the experimental drugs and vaccines now being considered for use in Africa’s Ebola outbreak have been developed in whole or in part with United States government biodefense funding, including ZMapp, the drug that appeared to help two American aid workers who were stricken with Ebola in Liberia.

Before it killed 13 people by unleashing nerve gas in the Tokyo subways in 1995, the Japanese cult Aum Shinrikyo traveled to Zaire, now known as the Democratic Republic of Congo. The trip was ostensibly a medical aid mission, but the real intent was to collect Ebola samples, according to a congressional investigation. It does not appear the cult succeeded in its quest.

The Soviet Union tried to develop a weapon using Ebola, but dropped the effort in favor of the closely related Marburg virus, said Raymond A. Zilinskas, director of the chemical and biological weapons nonproliferation program at the Monterey Institute of International Studies.

Dr. Zilinskas, who is a co-author of “The Soviet Biological Weapons Program: A History” (Harvard University Press, 2012), said the Soviets might have encountered difficulties in mass producing Ebola. He said they did manage to mass produce the Marburg virus in a form that could be stable if dispersed through the air, but he doubted that terrorists could do the same.

“You are talking about highly capable people working on it for years,” he said. “That’s not terrorists.”

A terrorist could expose himself to the infection, for example by rubbing against a corpse or by using bodily fluids from an infected person. That could be accomplished in West Africa, where many people are dying not in hospitals.

Ebola hemorrhagic fever has an incubation period estimated at two to 21 days, according to the World Health Organization. That means that many people would not have symptoms for a week or more after being exposed.

“So they could get on an airplane and get through customs and not be symptomatic and be in downtown Minneapolis before we know it,” Dr. Hall said.

Dr. Adalja said such a situation was not that plausible. He said that infected people are not contagious until they have symptoms, by which time they might not have the strength to go to a public place to infect others. And it would be hard for a suicide infector to spread the disease to others, since contact with bodily fluids is required.

“You have to literally vomit on them,” he said.

Researchers say that the inability of Ebola to be transmitted from person to person by air would also limit its effectiveness as a weapon of mass destruction. It is also not clear how stable the virus would be when exposed to ultraviolet light. Anthrax, by contrast, can be dispersed through the air in the form of very hardy spores.

One study by Army researchers showed that when forced to inhale Ebola virus, monkeys could be infected.

Another study published by Canadian scientists two years ago found that pigs could transmit the virus through the air to monkeys in nearby cages.

A version of this article appears in print on , Section A, Page 6 of the New York edition with the headline: Stabbing With Syringe in Nigeria Raises Concerns of Ebola as Weapon. Order Reprints | Today’s Paper | Subscribe